﻿Shader "ShaderBook/AlphaBlendZWrite"
{
    Properties
    {
        _Color("Main Tint", Color) = (1, 1, 1, 1)
        _MainTex("Main Tex", 2D) = "white" {}
        _AlphaScale("Alpha Scale", Range(0, 1)) = 1
    }
    SubShader
    {
        Tags {"Queue" = "AlphaTest"  "IgnoreProjector" = "True"  "RenderType" = "Transparent"}

        // Extra pass that renders to depth buffer only
        Pass{
            ZWrite On
            ColorMask 0     // 为0则不输出任何颜色
        }

        Pass
        {
            Tags {"LightMode" = "ForwardBase"}
            ZWrite Off
            Blend SrcAlpha OneMinusSrcAlpha
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            
            #include "Lighting.cginc"
            
            fixed4 _Color;
            sampler2D _MainTex;
            float4 _MainTex_ST;
            fixed _AlphaScale;

            struct a2v{
                float4 vertex : POSITION;
                float3 normal : NORMAL;
                float4 texcoord : TEXCOORD0;
            };
            struct v2f{
                float4 pos : SV_POSITION;
                float3 worldNormal : TEXCOORD0;
                float3 worldPos : TEXCOORD1;
                float2 uv : TEXCOORD2;
            };

            v2f vert(a2v v){
                v2f o;
                o.pos = UnityObjectToClipPos(v.vertex);
                
                o.worldNormal = UnityObjectToWorldNormal(v.normal);

                o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;

                o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);

                return o;
            }

            fixed4 frag(v2f i) : SV_Target{
                fixed3 worldNormal = normalize(i.worldNormal);
                fixed3 worldLightDir = normalize(UnityWorldSpaceLightDir(i.worldPos));

                fixed4 texColor = tex2D(_MainTex, i.uv);

                fixed3 albedo = texColor.rgb * _Color.rgb;
                
                fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz * albedo;

                fixed3 diffuse = _LightColor0.rgb * albedo * max(0, dot(worldNormal, worldLightDir));

                return fixed4(ambient + diffuse, texColor.a * _AlphaScale);
            }
            ENDCG
        }
    }
    Fallback "Diffuse"
}
